The best alternatives to Openroom are GitHub, Classmill, and ClassOwl. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Openroom?
AssemblyAI— Speech-to-Text API with superhuman accuracy
QuickSesh is a free online tool, which'll allow you to find relevant and random study sessions happening around the world! You can create/join a session, depending upon the availability. As of now, we're using Jitsi Meet, which is a FOSS conferencing website.
Kami is a web app that offers easy-to-use tools to millions needing a document and PDF solution. With the increasing number of American K-12 schools going paperless, Kami enables them to collaborate on publisher-supplied PDF files and worksheets using their Chromebooks or other devices.